The present disclosure relates to an imaging system. More particularly, the present disclosure to a high resolution coil array for a magnetic resonance imaging system.
Conventionally, magnetic resonance imaging (MRI) procedures include excitation of selected dipoles within a subject and receiving magnetic resonance signals emanating from the dipoles. In many applications, the magnetic resonance signals are received with whole body radio frequency (RF) coils, i.e. circularly cylindrical RF coils which surround a receiving bore of an MRI apparatus. In other applications, a surface coil is applied to a surface of a patient proximate to a region of interest (ROI) while the patient is located within the receiving bore to receive the magnetic resonance signals.
Various surface coil configurations have been utilized. Simple loop coils, e.g. a simple square or circle, have been utilized to receive the magnetic resonance signals. Loop coils are sensitive to signal components that are perpendicular to the loop coil and insensitive to components in a plane of the loop coil. In order to improve a signal-to-noise ratio (SNR), quadrature surface coils have been utilized to examine a ROI in quadrature, i.e. receive signal components that are perpendicular to the quadrature surface coil and components that are parallel to the quadrature surface coil. However, even these conventional quadrature surface coils produce under resolved images in certain regions of a body, such as, for example, in lower limbs.
In general, magnetic resonance imaging of vessels in the lower limbs has been poor in the past. Close proximity of calf and pedal arteries to a skin surface combined with fine characteristics of vessels in the lower limbs often results in under resolved images of the lower limbs. Orientations of vessels in the lower limbs also create imaging problems since, for example, a patient's feet are oriented in a separate plane than a majority of a body of the patient. Thus, existing commercial RF coils, often produce images of vessels, which are most distal that are of little diagnostic value.
Given the frequency and severity of diseases, for example, diabetes, that may require imaging of the lower limbs, it is desirable to produce a coil array capable of providing a resolution that provides improved images of the lower limbs. Additionally, since many patients having such diseases are aged or in pain, it is desirable to produce a coil array that is not compressive to wounds on the lower limbs.